The invention relates to a jointing system for joining pipes, especially copper plumbing pipes.
Conventionally, copper pipes are joined by compression-joints, consisting of brass fittings and shaped washers (olives). The jointing method is time consuming, costly, and requires specialist equipment. It also requires a skilled workman to effect a correct water-tight joint. A further disadvantage is that once joined, the olive which is shaped on fitting, cannot be reused. In addition, such joint fittings are often positioned in locations which are difficult to access with conventional spanners and the like.
Another known method of joining copper pipes involves soldered or pre-soldered joints. Whilst such systems require less skill, the joints formed are not reversible and/or adjustable after fitting. If the fitting leaks after installation it is difficult and time consuming to correct the problem. In addition, a blow torch is required which can be dangerous. Also, soldered joints cannot be reliably effected to old pipes or existing installations where the water has not been fully drained from the system.
GB-A-150150 describes a pipe coupling comprising a housing with open ends to receive pipe lengths and caps which are screwed to the housing in an effort to provide a sealed unit. The sealing system used is however very complex to assemble and inefficient in use.
GB-A-1556008 describes a modification to the coupling of GB 1520150 in an effort to provide improved sealing. However, again the seal is complex and inefficient.
GB-A-2075141 describes a coupling in the form of a unitary annular sleeve to receive pipe lengths. Separate annular grooves are provided in the sleeve with different types of seals in an effort to enhance the sealing effect. However, the sealing system is generally complex and inefficient. Further, the coupling is difficult to disassemble and apparently cannot be re-used.
GB-A-2254389 describes a system for forming sealing joints in pipe fittings. The fitting is internal of the pipe and will therefore cause a reduction in flow capacity. A complex fitting procedure is required which includes a double crimping operation. Therefore it would not be suitable for use in confined spaces. Further, the pipe would require very careful preparation by de-burning to ensure that the pipe can accept the fitting. Again the system is complex and inefficient.
U.S. Pat. No. 5,615,481 describes the production of highly complex circumferentially compressible pipe fittings. The pipe fitting is intended to be placed around a pipe end or stub. The body of the pipe fitting is formed with bulges to accept an O-ring seal. After insertion of the pipes a circumferential pressure is applied to squeeze the fitting around the pipes. The fitting is thus permanently in place and cannot easily be opened and especially cannot be re-used.
U.S. Pat No. 5,040,831 deals with a non-threaded pipe connection system in which pipes of different diameters are overlapped and a special tool is used to crimp the outer pipe onto the inner pipe. This tool has to be hammered into place which is not convenient as a confined area. The pipe may also be easily damaged on fitting.
U.S. Pat No. 5,413,388 describes a compression type pipe joint using a threaded clamp having a longitudianily slotted inner sleeve. The fitting is similar to a standard olive base system and suffers from similar disadvantages.
U.S. Pat No. 5,779,283 describes a non threaded pipe connection in which pipes are joined by an outer sleeve section. Pins are driven through the sleeve to deformably engage the pipes. This system is time-consuming and difficult, especially in confined spaces. The sealing is not efficient and the joint cannot be opened and re-made or re-used. The deformation of the pipe to receive the pins may not be regular and damage to the pipe and/or coupling may result.
There is therefore a need for an improved jointing system which will overcome these difficulties.
According to the invention there is provided a pipe fitting comprising:
a housing having at least one opening for receiving a pipe;
the housing having a pipe seal-receiving seat for receiving a circumferential seal; and
clamping means which is engagable with the housing for sealing engaging the seal against the pipe in the housing.
In an especially preferred embodiment of the invention the pipe has a circumferential groove for receiving the seal.
In one embodiment of the invention the clamping means comprises a cap.
Preferably the cap is screw threadingly engagable with the housing.
In a preferred embodiment of the invention the housing includes a stop means against which a free end of the pipe is engaged, on sealing.
In one embodiment of the invention the fitting includes locking means for locking the pipe in the fitting. Such a locking means would prevent unauthorised disassembly and removal of the fitting and associated pipework.
Preferably the locking means locks the clamping means to the housing.
In a preferred embodiment the locking means facilitates tightening of the clamping means beyond hand tightness.
Preferably the fitting includes a key for releasing the locking means.
In a preferred embodiment of the invention the locking means comprises keyengagable detents on the housing and/or the cap for tightening of the cap to the housing.
In one aspect the detents comprise a plurality of circumferentially spaced-apart teeth extending longitudinally are of the cap or housing and a key-receiving recess in the other of the cap or housing, the cap being rotatable on engagement of the key in the key-receiving recess and rotation of the key.
In one embodiment the fitting is a straight-through coupling having a pair of axially aligned pipe receiving openings.
In a particularly preferred embodiment of the invention the pipe is a pipe or pipe section having a circumferential groove formed in an outer wall thereof for receiving a complementary circumferential seal.
Most preferably the seal is mounted in the circumferential groove of the pipe. Ideally, the seal is an O-ring seal.
In a particularly important aspect the groove is formed a pre-set distance from a free end of the pipe or pipe section.
In one case the pipe is a copper pipe.
The housing may be of a metallic material or of a suitable plastics material.
In another embodiment the housing and/or the clamping means have means for sealingly engaging the seal against a pipe on closing of the clamping means.
Preferably the means for sealingly engaging the seal against a pipe comprises an open-ended circumferential slot in the housing, the seal being received in the slot on operation of the clamping means. Ideally the slot tapers inwardly from the open end thereof.
In a preferred embodiment the pipe is initially a push fit in the fitting and the clamping means is then tightened to sealingly engage the seal against the pipe.
In another aspect the invention provides a pipe working tool having an opening to receive a pipe or pipe section and groove forming means for forming a circumferential groove in an outer wall of the pipe.
In this case preferably the tool includes means for setting the location of the groove in relation to a datum.
In one embodiment the setting means is a stop means against which a free end of the pipe is engaged.
The tool preferably also includes cutting means for cutting a pipe to a desired length.
The tool preferably includes a pair of spaced-apart groove forming means and a cutting means between the groove forming means for forming a pair of grooves in a length of pipe and for cutting the pipe intermediate the grooves.
In a further aspect the invention provides a pipe or pipe section having a circumferential groove formed in the outer wall thereof for receiving a complementary circumferential seal.
In this case preferably the seal is an O-ring seal.
It is important that the groove is formed at a pre-set distance from a free end of the pipe or pipe section.
In one case the pipe is of a copper pipe.
The invention further provides a plumbing assembly including one or more of pipe or pipe sections of the invention and/or one or more pipe fittings of the invention and/or a pipe working tool of the invention.